Furnace for producing wood



'Oct. 16, 1945. c. MEYER 'FURNACE FOR PRODUCING WOOD CHARCOAL 4Shets-Sheet 1 Filed Dec.. 22, 1943 Oct. 16, 1945. c. MEYER' FURNACE FORPRODUCING WOOD CHARCOAL Filed-Dec. 22', 1943 4'SheetsSheet 2 c. MEYER 7FURNACE FOR PRODUCING WOOD CHARCOAL Filed Dec. 22, 194:5 4 sheets-sheet5 Deli. 16, 1945.-

c. MEYE R 2,386,972 .FURNACE FOR PRODUCING WOOD CHARCOAL D Filed Dec.22, 1945 4 Sheets-Sheet 4 Oct. 16, 1945.

Patented Oct. 16, 1945 FURNACE FOR PRODUCING WOOD CHARCOAL Curt Meyer,Buenos Aires, Argentina Application December 22, 1943, Serial No.515,298

' In Paraguay November 17, 1943 Claims.

This invention relates to the production of charcoal, and particularlyto a new furnace for the production of wood charcoal; v

Several charring methods are known, which have been improved With'thecourse of time so as to produce satisfactory results relative" to theold system based on mud covered piles of wood billets. However, thegeneral charrin-g process is still slow, and particularly the subsequentcooling which requires a period of around four "days.

Also, notwithstanding the improvements made, the methods and furnacesused for this purpose have several drawbacks which render theexploitation difiicult, particularly in view of the fact that due to themanner in which mean admission holes are arranged and the manner inwhichthe charge is kept in the furnace, the chambers are exposed to weatherconditions and affected by wind, rain and low temperatures, to theextent that in some cases and zones-it is only possible to char duringcertain seasons of the year.

Also, a close control should be kept of the furnace damper, as otherwisethe charcoal might be reduced to ashes. On the other hand, in order tochar with the known methods and furnaces, the wood should be wellstationed as otherwise, if green or recently cut wood isused, very poorresults will be obtained due to the extraordinary evaporation whichmight cause explosions which will alter the chamber walls as well as theauxiliary elements thereof. I

The present invention overcomes the above mentioned drawbacks byproviding two or more chambers so arranged that after the charrin iscompleted in one chamber, the cooling will be obtained throughabsorption of heat by the batch in the other chamber or chambers. Forthis purpose, intercommunication is established therebetween so that byradiation or thermosiphon the heat will be transmitted sufiiciently toobtain a fast drop of the temperature within the chamber containing thecharred wood, while at the same time the other chamber or chambers willacquire temperatures capable of further drying the wood and causing asemi-distillation suflicientto char the wood in a short time during thesubsequent cycle.

In carrying out the present. invention, a double furnace formed by twinchambers is preferably used, said chambers communicating with each otherat the top and at the bottom, and being provided with dampers and meansfor facilitating the handling thereof so that whilethe wood billets arebeing charred in on chamber, the other chamber will remain as anintermediary chamber so that the draft towards the chimney willpreheatthe charge or batch, to be charred in the subsequent cycle. Once thecharring has been completed in the first chamber, the general inlets andoutlets are closed and free. communication is established between bothchambers so that an exchange will be produced by thermosiphon. therebycausing the quick cooling or the charred wood, while at the same timetaking advantage of the heat to further dry and condition the wood, inthe other chamber to be charred during the next cycle.

Apart from the above, the invention contemplates other objects, amongwhich is the obtention of a maximum yield, not only due to thedevelopment of the process itself, but also to the fast manner in whichthe cooling step takes place, which renders it possible to operate atthe rate of more than one complete cycle per day, since this step can becompleted in a, period of from seven to ten hours.

A further object of the invention is to operate in' an alternativemanner with the two chambers, so that the workmay be carried out in yasub.-

stantially continuousmanner for production on I a large scale. For thispurpose, while the char. ring is taking place in one chamber, the otherchamber will remain as a secondary chamber or the conditioning of thebatch therein, and once the first cycle is completed, the action of thechambers is reversed.

A still further object of the invention is to. provide a furnace whichwill enable the satisfactory charring of fresh cut wood, inasmuch as thepica-conditioning mentioned above will dry same, thereby placing it incondition for charring.

A still further object of the invention is to obtain a highyield of woodcharcoal of a homogeneous quality, suitable for diiferent industries, aswell as for domestic use.

A still further object of the invention is to provide apparatus forcharring woodwhich will involve an economy in the general exploitation,not only due to the high yield but also to the low labour costs'involvedin view of the simple operation of the furnace.

A further object of the invention is to provide apparatus which will besafe in operation and eliminate danger of burning the wood charged inthe chambers.

A still further object. of the invention is to provide a furnacewhichmay be readily taken apart, transported and reassembled- .A stillfurther object or the invention is to with the accompanying drawings,illustrating by way of example two preferred manners of carrying outthe,charring process. I

In the'drawing'si .i Fig. 1 is a sectional view of nace, taken along theline NN of Fig. 2.

Fig. 2 shows partial cross-sectional plan views of the same furnace.

the charring fur:

Fig. 3 is a'sectional view of the furnace, taken 5 along the line S-S ofFig. 2, showing all the air intakes and outlets in closed position afterthe completion of the charring operation -in' onecf the chambers; and

Fig. 4 shows a somewhat modified form of furnace wherein each h m e e. lV

*fIhesame reference characters are used to indicate likeor correspondingparts or elements throughout the drawings. 'f

Asmay be seen in Figs. 1, 2 and 3, the furnace comprises twin chambers aand 1) adjacent to each other and having a; common wall I thecentra'lportion of which isprovided with a'chimney c which is alsocommon toboth chambers; Thus, each chamber is provided with an openinghaving a grid 3; and since the chambers are to be used alternately, eachopening. 2 isprovided with agate 4 slidably mounted on vertical guides5;; and 'as'clearly shown in Figs. 1 and 3 said chimney c terminates'witha' hinged cover 6 actuated byi means'of acable 8 guided ona sheave9. Eachofjthechambers a and bare provided with auxiliaryfsets of airintakes, l0 having hinged covers ll and capable of being tightly closedaiter'the admission of a certainamount of air necessary for carrying outthecharring process. Each of the chambers a andb isprovided'with afireplace l2 constituted bypassages having 'a slightly sloped bottom'and' located against the chamber is provided with a wall Land a'sclea'rly showninjthe drawingsfsaid firepl ces l2" are providedlwi'thfaplurality of air intakes l'Sstarting at'th underground chanfilfl ll'f IK Access to fireplaces I2 is provided by means of rear mouths I5,having" tight closing covers l5, of the respective chambersdand b, saidfireplaces being. capableof receiving cages 16 made of iron or'othersuitable material and housing a charge ofldoal and wood for starting thefiring or the furnace,l since Isaid fireplaces have open frontsleadingto the interior of th furnacecontaining the woodbilletsl'l. I

chamber a, l) is provided with a plane l8 forming a step with the floorl8 and formed by a slab supported by partitions 20. Said plane. I 8 iskept in spaced relation to the slab l 9, thereby constituting,underneath the slabs of plane 18, a plurality; of conduits 2| extendingthroughout the width of the chamber and sloping towards the middleline-of; the furnace;vvl'ie re,;by means of passage 22, theconduits-g2}, of, the chambers communicate with; ,each other,asgraphically shown inFigs. 1 and}; thus, it ispossible to establish aconnection between chambers a and .1) through said conduits 2i andpassage 22. i

,Passage; 22is providedwitha container. 23 for collecting-tar: andgcrudeaceticgacid as by-products of the distillation. 131;. .'Apart .fromthefintercommunication through passage 22 connecting said conduits 2!,coinmunication between both chambers may be established by means of apassage 24 located at the upper portion, as shown in Figs. 2 and 3, saidpassage being in turn provided with a gate 25 which should be keptclosed during the charring operation. As will be explained hereinafter,said gate 25 should only be opened after completing the charmingoperation in one chamber and for the purpose of cooling the furnace bythermosiphon.

, .Said chambers a and b are provided with doors 26 of a size sufficientto readily allow the charging of wood and the removal of the charcoalresulting from the process; however, said doors should be provided withmeans to enable a tight closure thereof during the operation of thefurnace.

Said underground channel I4 is provided with a general opening 14'having a tight closing hingedcover 21, as shown in Fig. 2;

In the embodiment of Fig. 4, chambers a and b are of the'usual typehaving air intakes 28 and a corresponding closure 28', andas may be seenfrom the drawings, each chamber comprises a chimney 29 having a closinggate 38.

The lower portion of chambers a. and b communicates with conduit 3|having a gate 32, while the upper portion of said chambers communicatesthrough a conduit 33 also provided with a gate 34. 1

Both the furnace shown in Figs. 1, 2 and 3 and that illustrated in Fig.4, are provided withpyrometers 35 for the purpose of controlling thefiring process.

Operation In order to char with the furnace shown in Figs. 1, Zand 3,both chambers a and b are charged with wood billets. If it is desired tofirst'operate with the chamber a, the gate 4 of opening 2 in saidchambera'should be closed, while gate 4 of opening '2 in chamber b is opened asshown in Fig-1.

. Cover 21 for the admission of air through mouth l4 providing accessto' channel l4 of air intakes I3 corresponding tofireplaces 12 shouldalsobe opened, and cover 6 of draft chimney 0 should also be in openposition as indicated in Fig. 1, thus remainingas an outlet for chamberb serving in this instance as intermediary to chamber a. Gate 25 shouldbe kept closed. v I

Cover l5 of chamber a (Fig; 2) is opened and cage l6 containing thenecessary fire for starting the charring operation is introduced throughmouth l5. As mentioned hereinbefor said cage is placed in the fireplacel2 so-that after closing the mouth 15 by means offcoverj IS the furnacewill remain in'operating condition; V v

The fire of the fuel in cage I6 located within the fireplace IZLofchamber a will'extend to the wood billets ll constituting'the" chargeofsa'id furnace, thereby producing the combustion with the draft asindicated by the arrows in Fig. 1, via, after the revolution in chambera, the'combustion gases will flow through conduit 2| of chamber a,passage 22 and conduits 21 in chamber 1), thereby entering the latterwhere'they will infiltrate through the wood billets ll" until they'reachthe opening 2, from where said gases will pass to chimney c and throughsame to the atmosphere J The heatof said gases will cause a previoussemi-distillation in the billets ll charged withr in chamber b, so thatas the charring of the bilchamber 1) will beconditioned for thesubsequent charring thereof.

The charringprocess is controlled by means of pyrometers 35 and otherinstrumentswhich may be applied to the intakes Ill which in turn serveas windows, and once the charring process has reached. a critical point,the main intakes l3 are closed by closing opening M by means of cover27, so that upon opening the inlets ID, the ignition diffusing step willbe initiated; since due to the change in position of the air intake,there will he a gradual lowering of the. mass-of lire in the charge inchamber a. Thereafter, the gradual l sure of co s it will initiate astep which could be termed of fcookin of. the entiremass and in whichthe charring is completed, not only of the. material comprised in themain. direction of the ignition course aided by the dra t also of; thatcorrespondng to the corners. of said .cham ber a, as due to the lackiofa .free draft. the heat is diffused in a balanced and substant a lydistributed manner.

After this cooking period, cover 6 of chimney c should be, cl sed, andalso gate 4 of opening 2 corresp nding o chamber o as to b ock anypossible exhaust of valuable gases and keep both chambers tightlyclosed.

Throughout the process, the tar and acetic acid as by-products of thedistillation, will run on the inclined floor I9 and be collected incollector 23.

The opening of gate 25 as shown in Fig. 3, will initiate the process ofcooling the material in the furnace, which takes place in asubstantially quick manner, due to the fact that upon opening the gate25, both chambers 11 and b will communicate by means of passage 24 bothfrom the top and the bottom portions, as shown in Fig. 3, whereby theheat of the material within chamber a will pass to that in chamber b asshown by the arrows in Fig. 3, in a closed thermosiphon circuit withreturn by means of conduits 2| and passage 22.

During this cooling period, the material I'I' in chamber 7) will absorbthe heat in chamber a in such a manner that the conditioning thereofwill assume the nature of a semi-distillation, ready for charring in thesubsequent cycle through a brief combustion process of less than Ihours.

In this manner, the cooling may be obtained in a period of approximatelyl0 hours, so that after same has been completed, gates 25 of conduits 24should be closed, and the doors 23 of chamber it opened so as towithdraw the charcoal resulting from the operation and to recharge samewith wood billets.

After recharging with wood billets, mouth I4 is opened by lifting thecover 21, whereby the furnace will remain in the conditions shown inFig. 1, with the difference that the gate 4 of mouth 2 corresponding tochamber 2) should remain closed, while gate 4 corresponding to chamber ashould remain open, as in this instance chamber 11 will act as primarychamber, while chamber a will remain as secondary chamber. A cage l6containing burning fuel should be inserted through mouth of chamber b,so as to initiate the combustion of the preconditioned material inchamber b which is readily charred, with draft through conduits 2! andpassages 22, that is to say, with the intervention of chamber a throughwhich the combustion gases will circulate before being exhausted throughchimney c.

As in the previous cycle, once the critical point is reached, the mainintake I4 is closed and the air intakes [0 are opened so as to reducethe fire in chamber ib." whereafter'the covers l-l aregradually closedsothat the material will start a "cooking" periodfor the purpose ofobtaining a complete and uniform charring, Finally,upon closing allgates'andintercommunicating both chambers, the opening. of gate 25, willinitiate the cooling process in which by thermosiphonthe heat will passfrom one chamber to another, with the consequent advantage of the heatfor conditioning the secondary chamber.

. n the case of the furnace shown in Fig. 4, the charring of thematerial IT in chamber a will take place in the usual manner, by closinggates 32 and 34 and openingthe covers of air intakes 28 and draft gate30.

After completing the charring operation in the usual'manner, covers 28'and gate v3i! should be closed, while the opening of gates 32 and 34will communicate chambe a, with chamber b, containing a charge of woodbillets. Said chamber 12 should also be, closed.

After communicating both chambers a and b through conduits 3i and 33,the heat of the charge in chamber a will be greatly absorbed by thecharge, in chamber b, either by radiation or by thermosiphon, therebyobtaining a. substantially fast cooling of the charred charge in chambera and the advantageous use of the heat for further drying andconditioning the wood in chamber b.

After the completion of the cooling process, gates 32 and 34 are closedand the charred charge in chamber a is removed and a fresh charge ofwood billets placed therein.

The charge l1, already conditioned in chamber b is in turn ignited forcharring in the usual manner but in a short period of time, since saidconditioning involves a previous semi-distillation reatly reducing theduration of the charring step itself.

After completing, the charring of the wood in chamber b, the air intakesand draft thereof are closed (covers 28' and gate 30), therebyinitiating the cooling process, for which purpose gates 32 and 34 areopened so as to communicate with chamber a by means of conduits 3| and33, so that the heat will be absorbed by the charge in the latterchamber.

Summarizing, the process for the production of wood charcoal is carriedout with two or more charges of wood so that after charring one charge,the cooling of said charge will take place by transmitting the heat tothe other chamber so that the charge to be subsequently charred willabsorb the heat of the charred wood and at the same time obtain a quickcooling of the charred material. The heat absorbed by the chamber orchambers containing uncharred wood will condition the latter, ready forsubsequent charring and cooling in the same manner.

It is evident that in carrying the invention into practice, severalmodifications, alterations and changes will occur to those skilled inthe art, Without departing from the scope of the present invention asclearly set forth in the appended claims.

I claim:

1. A wood charring furnace comprising twin charring chamberscommunicating with each other both at the top and at the bottom thereof,a gate for closing at least the communication at the upper portion ofsaid chambers, said chambers having air intakes with correspondingdampers a fireplace in each chamber for initial ignition, said chambershaving a chimney and means for closing the draft to said chimney and 4-aasao'za a cover-for 1 closing said; chimney, anthem-hers having aifioorsloping towards a collcto'rI for.by-'

wardsfthe middle lineand 'having acommon in- 5 berscommunicatingwitheachbtherii -2. A wood charring furnac" comprising twin chartinchambers communicating with each tel-mediate passage, the conduits of'both' chamother both at the top 'and at thel bottom thereof,

ignition, said chambers having a chimhy and means {or closing the draftto said chimney-and a cover for closing said chimney, said fireplacesconstituting passages each having an'intak e provided with a. cover;with each passage provided with. an underground admission, said passagesopenin towards the middle of the furnace and being adapted'to receivefuel "holding cages for the initial combustion of the charge? 7 V 3. AWood charring furnace asclaimed in claim 2, wherein'saidfireplaces are:provided with a plurality of auxiliary intakes having a pluralityof-tightclosing covers. j 4; 'A' wood charring furnace comprising twin:charring chambers communicating with' each other both at the top and atthe bottom thereof,

'a gate foriclosing at least the communication at 'theiupperiportionfofsaidchambers, said chambers ihavin flairi intakes with correspondingdampers afire'plac'in each :chamber for initial ignition, s'aid chambershaving a" chimney and I means 'for closing the draft to: said chimneyand a cover for. closing said-;chimney,.-each of said chambers'lhavingan opening leading to a common chimneyand provided with aclosing gate,said chimney having a cover and means for actuatingsaidcover. f

l 5; A Wood charring furnace. comprising twin char-ring chamberscommunicating with each other both atthe top and.- at the bottomthereof, agate for closingatleast 'the communication at the upperportion of saidchambers, said chambershaving air'intakes withcorresponding damp ersa fireplace in-eachchamber for initial ignition,said chambers having-a chimney and means for closing the draft to saidchimney and a, cover for closing 'said chimney; saidchambers beingadjacent the upwardly located communication, said chambers beingarranged wholly beyond and on opposite sides of the chimney.

CURT MEYER.

